The field of pill-dispensing features many different mechanisms that are designed to recognize, sort and count tablets and capsules of all types and sizes. Many of these devices are problematical, due to their lack of reliability. In order for one apparatus to properly recognize and/or sort differently-sized pills, for instance, it has often been necessary to modify dispenser design, so as to accommodate tablets of particular shapes and sizes. Oftentimes, adjustments must be made to a machine during the operation thereof. Such changes greatly inhibit the use of such devices in facilities that are automated or are continuously run.
The present invention illustrates a new apparatus that is both reliable and able to handle a wide variety of tablets and capsules, without the basic design requiring adjustments or modification thereto.
The current invention is a standardized or universal-type module that can be easily loaded with a hopper having all types of tablets and capsules of varying size and shape. The module has a simple, screw-type feed and dispensing mechanism that can operate at different speeds to accommodate the different pills. A multiplicity of modules can be arrayed in a workstation that is computer-controlled. The speed of each dispensing mechanism is also computer-controlled, so that each module can be individualized for a specific pill. In this manner, the workstation can dispense a wide range of pills as needed in any sort of applicable prescription filling facility (e.g., retail pharmacy, hospital pharmacy, clinics, nursing home, mail-order concern).
This invention is more cost-effective and compact than existing dispensers. It is able to count accurately at a speed commensurate with a high-throughput pharmacy fulfillment system. Its design allows for its use in banks or arrays which are compact enough to allow a single operator to handle 200 or more dispensers from a single workstation. The form of the device also allows its use in a pre-existing, automated dispensing- or prepackaging facility, which can accommodate the invention quite affordably.
As aforementioned, this invention provides a basic design that can handle a complete range of tablet and capsule sizes and shapes, without requiring different mechanical operations or adjustments. The inventive, basic design is controlled electronically. A microprocessor is programmable so as to provide different drive voltages that adjust the timing and operation of the mechanism, which, in turn, set the device to operate specifically with respect to a particular pill or tablet.
The mechanism of the invention features a sloped tube containing a helical, interior ridge. The tube is set at an angle to the horizontal plane. With its helical ridge, the sloped tube is rotated, causing tablets fed to the mouth of the tube to move upwardly along the tube, against gravity, and thereby becoming separated, either individually or into smaller groups. As the pills reach the end of the tube, they are individually separated, and can be accurately dispensed from the end thereof. The falling pills are then detected individually by photodetector cells, and are thereby reliably counted. The computer controlling the dispensing operation is programmed to recognize a double-feed or a broken, fragmented tablet.
U.S. Pat. No. 5,213,232, issued to KRAFT et al, discloses an apparatus for dispensing single units such as pills. A generally circular, walled container has a bottom for holding the units and a discharge area located distally from the bottom for receiving the single units and for discharging them upon manual rotation. A helical spiraled rib member is located on the circular walled container for creating, during rotation, a continuously variable inclined surface along the helical spiraled rib member and the circular walls of the container. In addition to requiring the bottom (making it impossible to incorporate in a system with a hopper), the system is not adapted to be automatically advanced.
Screw-feed separation and photoelectric counting are known in the art. The invention features such significant improvements over the existing concept, however, that, while the basic simplicity and reliability are retained, both speed and accuracy are enhanced. The key to the maintenance-free reliability sought is in its basic simplicity. The incorporated improvements to the basic design provide significant changes in operational features, speed and accuracy. Therefore, while being sophisticated, the invention retains basic simplicity.
Providing accurate, pill-dispensing counts for differently-sized and -shaped tablets via a single mechanism is a complex problem sought by many, and accomplished by few. It is the purest form of invention which takes a complex problem and makes it simple, as has been done here.
The inventive mechanism improves the separation of the tablets within the screw-feed, a process often referred to in this art as singulation. The invention is an improvement over a basic, screw-feed mechanism, making certain that only single pills emerge from the dispensing end of the tube.
The inventors have discovered that several factors influence the singulation process in the screw-feed of the present invention, to wit: (a) the size and shape of the helical ridge, (b) the slope of the tube containing the helical ridge, (c) the pitch from one turn of the helical ridge to the next, and (d) certain other shapes interior to the device must be designed to cause some of the tablets to tumble backward over the helical ridge, thus stringing out the forward portion of the tablet mass into a single-file configuration within the helix. The design of this backward tumbling ensures singulation. The backward tumbling limits the number of tablets being carried forward by any one 360.degree. turn of the helix. This, in turn, causes the tablets to emerge from the dispensing end of the device only one at a time.
The screw-feed mechanism of the pill-dispensing apparatus of this invention rigidly connects a helical ridge, or a helix, to the inside wall of a rotating, hollow tube. The ridge is designed to extend beyond the upper end of the tube for approximately one turn. At this end, the helix is encased by, but is not connected to, a stationary collar having the same diameter as that of the rotating tube. As the helix advances within the stationary collar, it pushes tablets out of the collar. The pills typically exit only one at a time, and are then reliably counted by a photoelectric device. The shape of the helical ridge causes the tablets to lie essentially flat as they are pushed along this stationary collar. This further ensures that the pills will fall out of the collar only one at a time.
The helical ridge is bent slightly at its output end (towards the output end of the helix), which causes a further separation of the tablets as they fall from the dispensing end of the collar. The helix pitch is lengthened over a forward portion thereof, in order to effect better separation of the pills as they travel along the tube.
Two protrusions, or, nubs, are built into the inside of the rotating hollow tube, between two turns of the helix. These protrusions assist in causing excessively large tablets to tumble backwardly towards the input end of the helix. The leading edge of the helical ridge is angled downwardly and to the left, in order to urge the tablets backwardly toward the mouth of the hollow tube. Thus, large pills that were successful in moving towards the dispensing end are pushed backwards, and the forward pill mass achieves a greater separation from the main batch.
Two small protrusions are built into the face of the helical ridge, up against the inside of the rotating tube. These small protrusions are disposed on the output side of the ridge approximately one, and one-and-a-half turns, respectively, on the helix, from its output end. These protrusions assist in causing excessively small pills to tumble backwardly towards the input end of the helix. Thus, small pills that were successful in moving towards the dispensing end are pushed backwards, and the forward pill mass achieves a greater separation from the main batch.
Thus, the inventive protrusions provide a built-in, inherent compensation for both small- and large pill separation. Thus, the inventive apparatus does not require operational adjustments, which are so common in the devices of the prior art.
As the helix-tube combination turns, it picks up tablets from a hopper, bringing them into the tube. At the input end, or, mouth, of the helix-tube, a trough is disposed adjacent the bottom of the hopper that contains the supply of tablets. The trough is pivoted at one end away from the mouth of the helix-tube, and is bias-spring supported at a point adjacent the mouth thereof. This trough is thereby enabled to tilt downwardly at its end, adjacent the helix-tube mouth. In the event of a tablet jam at the input end (mouth portion), the force and the weight of the jam will cause the pivoted trough to tilt against its spring biasing, relieving the pressure of the jam, and thus allowing tablets to once again flow freely into the helix-tube.
The microprocessor controlling the dispensing mechanism stops the rotation of the tube when the number of tablets counted by the device approaches the number desired for a given dispensing count. Afterwards, the microprocessor intermittently rotates the tube in both a forward and reverse direction a fraction of a turn, waiting between successive, intermittent jogs for a signal from the photodetector that the final tablet in the count has dropped therethrough. This intermittent rotation at the end of the dispensing cycle reduces the tendency of multiple pills to drop from the end of the tube. In this fashion, the microprocessor control ensures that an accurate, final count of tablets will be obtained. The size of the small, incremental angle and the duration of the wait are adjusted in software to be optimal for the size of the pills being dispensed. In this way, the only adjustment required to accommodate the different sizes of pills is accomplished in software that affects the helix rotation only. No mechanical modifications or adjustments are required therefor.
As a result of maintaining the simple concept of a screw-feed drive, the device maintains its overall reliability, which is further enhanced by the improvements. The refinements in both hardware and software to the basic, helical, screw-feed drive achieve simplicity, reliability, low cost and compactness for this pill-dispensing system.